UA 2809 then AA 3974 at O'Hare
Fort Lauderdale → Chicago → Harrisburg
Timetable, Chicago time
09:31UA 2809 from Fort Lauderdale at the gate
08:27AA 3974 to Harrisburg leaves the gate
22 h 56 apart on the timetable, overnight
AA 3974 leaves 22 h 56 after UA 2809 arrives on the timetable: more than half a day, so not a connection we count.